[quote=walterwhite]Wait not so fast. The op has to investigate his reasons why.[/quote]

No. He really doesn’t have to investigate the reasons.
Race is the projection of social characteristics based on physical characteristics (typically by observable phenotypes).

Using that (honestly irrelevant) criterion as a basis of acceptability of tenant quality is (by definition) racist.
It is also a very stupid way of evaluating tenants.

His motivations for being racist are not important to defining whether or not he is a racist.

Relevant criteria for tenancy are:
Credit report.
Eviction history.
Criminal record.
Level of income.

Also, the OP could be sued super-badly by using protected classes.
I had a client ask me to do that.
I told him to find another manager/agent.

Long-winded examples:

Dark skin, thick lips, and fuzzy hair define someone as “black”.
Being “black” connotes, but do not necessarily denote, African origin.
African origin in the US connotes, but does not necessarily denote, descent from slaves.
Descent from slaves can connote lower social class and less affluence.
Lower class can connote propensity toward criminality.
Criminality is undesirable in a tenant.

Here is the problem with that chain:
It is literally true but complete bullshit.
Most welfare recipients are white.
Most criminals are white.
Our president is black and of African descent but not a descendant of slaves.
His wife is descendant of slaves but is a very affluent lawyer.
Virtually ALL Jews are descended from slaves (remember Passover?).
Jews are not known as low-class, criminals, or bad tenants.

Also:
Arabs are members of the Caucasoid (white) Race.
So are Jews.

If you deny quality tenants for being black (unnecessarily) then you probably are letting in deadbeats because they are white.

The bottom line is this:
If you are using wrong-headed evaluations, then you are using wrong-headed evaluations.
Its that simple.
And yeah, you are a racist.